1. Field of the Invention
The present invention relates to an ink jet printer. In particular, the present invention relates to an ink jet printer for forming an image by using high viscosity ink.
2. Description of Related Art
According to an earlier development, an ink jet printer has a recording head having nozzles for jetting ink onto a recording medium. The conventional ink jet printer has an ink supply section for supplying ink in an upper position of the recording head, and an intermediate tank for temporarily storing ink supplied from the ink supply section in a lower position of the recording head. Ink is fed from the intermediate tank to the recording head through an ink supply line. In this ink jet printer, because the intermediate tank is disposed in a lower position of the recording head, negative pressure is applied to ink of the nozzles.
In the ink jet printer according to an earlier development, regardless of the viscosity of the ink to be used and the amount of ink to be jetted per second, a length and a diameter of the ink supply line are defined only by the request of mechanism. However, in case high viscosity ink is used, friction resistance of the ink supply line causes pressure loss. Thereby, for example, in case ink is continuously jetted from all of the nozzles, the proper amount of ink is not supplied to the recording head, which may result in abnormal jetting of ink. For that, there is an ink jet printer having a pressure supply system of ink for pushing ink to the recording head (Japanese patent No.2980476).
However, in an ink jet printer according to an earlier development, because a pressure supply system was disposed, there was a problem that design was complicated and the cost thereof was high.